Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
The particular size of wind turbine rotor blades is a significant factor contributing to the overall efficiency of the wind turbine. Specifically, increases in the length or span of a rotor blade may generally lead to an overall increase in the energy production of a wind turbine. Accordingly, efforts to increase the size of rotor blades aid in the continuing growth of wind turbine technology and the adoption of wind energy as an alternative energy source. However, as rotor blade sizes increase, so do the loads transferred through the blades to other components of the wind turbine (e.g., the wind turbine hub and other components). For example, longer rotor blades result in higher loads due to the increased mass of the blades as well as the increased aerodynamic loads acting along the span of the blade. Such increased loads can be particularly problematic in high-speed wind conditions, as the loads transferred through the rotor blades may exceed the load-bearing capabilities of other wind turbine components.
Certain features, such as spoilers, are known that may be utilized to alter the flow of air from the outer surface of a rotor blade, thereby reducing the lift generated by the blade and reducing the loads acting on the blade, and thus further reducing undesirable deflection of the rotor blade. However, these features are typically designed to be permanently disposed along the outer surface of the rotor blade. As such, the amount of lift generated by the rotor blade is reduced regardless of the conditions in which the wind turbine is operating. Further, in cases where such features are movable, the features are typically active features that require controllers and actuators to deploy the features as desired. These controllers, actuators, and other components required for active features are expensive and can be easily damaged during operation of the wind turbine.
Accordingly, an improved rotor blade assembly for a wind turbine would be desired in the art. For example, a rotor blade assembly including a passive spoiler assembly would be advantageous.